Debugging our pipeline code

Debugging with VS Code

Setup

Create or modify .vscode/launch.json in your project root:

{
    "version": "0.2.0",
    "configurations": [
        {
            "name": "kedro run",
            "type": "debugpy",
            "request": "launch",
            "module": "kedro",
            "args": ["run"],
            "cwd": "${workspaceFolder}/pipelines/your_pipeline"
        }
    ]
}

Common Debug Configurations

Here are some useful debug configurations for Kedro:

{
    "version": "0.2.0",
    "configurations": [
        {
            "name": "Run Full Pipeline",
            "type": "debugpy",
            "request": "launch", 
            "module": "kedro",
            "args": ["run"],
            "cwd": "${workspaceFolder}/pipelines/your_pipeline"
        },
        {
            "name": "Run Specific Nodes",
            "type": "debugpy",
            "request": "launch",
            "module": "kedro",
            "args": ["run", "--nodes", "node1,node2"],
            "cwd": "${workspaceFolder}/pipelines/your_pipeline"
        },
        {
            "name": "Run with Different Env",
            "type": "debugpy", 
            "request": "launch",
            "module": "kedro",
            "args": ["run", "-e", "test"],
            "cwd": "${workspaceFolder}/pipelines/your_pipeline"
        }
    ]
}

Using the Debugger

Set breakpoints by clicking to the left of the line numbers in your code
Select your debug configuration from the dropdown in the Debug view
Start debugging by pressing F5 or clicking the green play button

Debug Variables and Watch

Use the Variables pane to inspect local and global variables
Add expressions to the Watch pane to monitor specific values
Use the Debug Console to evaluate expressions in the current context

Advanced Debugging

Node-specific Debugging

To debug specific nodes in your pipeline:

{
    "name": "Debug Specific Node",
    "type": "debugpy",
    "request": "launch",
    "module": "kedro",
    "args": ["run", "--nodes", "target_node"],
    "cwd": "${workspaceFolder}/pipelines/your_pipeline"
}

Pipeline Slicing

Debug a slice of your pipeline:

{
    "name": "Debug Pipeline Slice",
    "type": "debugpy",
    "request": "launch",
    "module": "kedro",
    "args": ["run", "--from-nodes", "start_node", "--to-nodes", "end_node"],
    "cwd": "${workspaceFolder}/pipelines/your_pipeline"
}

Additional Resources

Tips and Tricks

Use conditional breakpoints by right-clicking on a breakpoint
Enable "Just My Code" to avoid stepping into library code
Use logpoints for non-breaking debugging messages
Utilize the "Debug Console" for interactive debugging

Common Issues

Missing debugpy: Ensure debugpy is installed in your environment
```
pip install debugpy
```
Wrong Working Directory: Make sure the cwd in launch.json points to your pipeline directory
Environment Issues: Verify VS Code is using the correct Python interpreter with your Kedro environment